C++17: I See a Monad in Your Future!

[If you prefer, you may watch the video of my talk on this topic (here are the slides).]

If you thought you were safe from functional programming in your cozy(舒适的) C++ niche, think again! First the lambdas and function objects and now the monad camouflaged(伪装) as std::future. But do not despair(绝望), it’s all just patterns. You won’t find them in the Gang of Four book, but once you see them, they will become obvious.

NOTE: 如果您认为在您舒适的c++领域中可以避免函数式编程，那么请三思! 首先是lambdas和函数对象，现在的单子伪装为' std::future '。 但不要绝望，这只是模式。你不会在“四人帮”的书中找到他们，但是一旦你看到他们，他们就会变得很明显。

Let me give you some background: I was very disappointed with the design of C++11 std::future. I described my misgivings(担忧) in: Broken Promises — C++0x futures. I also made a few suggestions as how to fix it: Futures Done Right. Five years went by and, lo and behold, a proposal to improve std::future and related API, N3721, was presented to the Standards Committee for discussion. I thought it would be a no brainer, since the proposal was fixing obvious holes in the original design. A week ago I attended the meetings of the C++ Standards Committee in Issaquah — since it was within driving distance from me — and was I in for a surprise! Apparently some design patterns that form the foundation of functional programming are not obvious to everybody. So now I find myself on the other side of the discussion and will try to explain why the improved design of std::future is right.